Many devices use light emitting diodes (LEDs), such as flashlights, traffic control signals, flat panel displays, mobile telephone displays, vehicle taillights, and light bulbs. The LEDs are typically current-driven devices, meaning the LEDs are controlled by regulating the amount of current flowing through the LEDs. Ideally, the current supplied to one or more LEDs is controlled at a minimal cost.
LED control has often involved regulating the peak current through the LEDs. While other LED control techniques have attempted to control the average current through the LEDs, these techniques often suffer from various disadvantages. These disadvantages have included poor transient response, excessive die space, and limitations on operating frequencies, input voltages, and output voltages.